In response to someones question about GIMP.
GIMP is open source (i.e. community built freeware) raster image manipulation software that gives you many of the capabilities of Photoshop without the financial investment. While the user interface is not as user friendly as Photoshop (at first glance) it is very functional.
GIMP uses the same layer set up as Photoshop and has the ability to be augmented with a plethora of plug ins. Currently, there are over 100 plug ins available! It has a scripting interface that allows you to set up standard task scripts that will save you a ton of time if you process a lot of pictures the same way (everything from simply resizing to a specific size and renaming the file to very complex scripts).
You have a very good selection of file types to work with: bmp, gif, jpeg, mng, pcx, pdf, png, ps, psd, svg, tiff, tga, xpm, as well as others.
You can use GIMP to eliminate barrel distortion and perspective distortion (great for windows and doors that look distorted)....channel mixing, digital retouching....was that bathroom missing a mirror when you took the photo? That's ok, with GIMP, you can add one back in!
There are a ton of brushes and selection tools that will really help you bring your pictures to the place that you want them to be. Like any other software that is available, there is a learning curve. Some folks can do amazing things with GIMP, while others will have trouble opening up a picture in it.
I love my Photoshop, but, I am a professional photographer. If you are interested in trying GIMP, you can go to the following website and download it for free. Remember, there is no warranty with GIMP, but hey....Its FREE!!